中文摘要：

本文以COHA、COCA两个美国语料库提供的大量客观、真实的数据为依据,探讨CRISIS在近200年的历时演变及其搭配词的特征,以期从话语研究中获取美国的经济状况信息。研究表明：（1）从20世纪30年代开始,CRISIS的使用频率突然飙升,而后一直都是美国大众关注的重点;（2）CRISIS的搭配词具有很强的商务性倾向,ECONOMIC CRISIS与FINANCIAL CRISIS共现频率最高;ECONOMIC CRISIS与ENERGY CRISIS分别对应20世纪30年代和70年代美国面临的最严重的两次危机,也成为了这两个时期美国经济的标志性事件;（3）在动词性搭配词方面,最常见的搭配词是FACING。统计对比后发现,应对危机的具有积极语义韵动词在语料库中共现的频率高于具有消极语义韵的动词,这表明美国社会在积极寻求解决危机的途径与方法。

英文摘要：

Based on a large number of objective, factual data in COHA and COCA, this research explores the evolution of CRISIS during the past 200 years and its features of collocation in order to interpret the American economy from the perspective of discourse studies. The results of research have shown that： 1 ） in the 1930s, CRISIS suddenly surged in frequency of use, and from then on, it has become the public concern of the United States; 2 ） the collocations of CRISIS are likely to fall into the category of business. ECONOMIC CRISIS and FINANCIAL CRISIS demonstrate the highest frequency; ECONOMIC CRISIS and ENERGY CRISIS refer to the most serious crisis facing the United States in the 1930s and 1970s respectively, which became a landmark in the American economy; 3 ） for the verb-collocations, the most common collocation is FACING. The statistical comparison indicates that words with positive semantic prosody are used more frequently than those with negative semantic prosody, suggesting that American society is actively seeking ways to address the crises.